Die Bodenkultur - Journal for Land Management, Food and Environment

R. Nolz, G. Kammerer and P. Cepuder:

Improving interpretation of lysimeter weighing data


Weighing lysimeters are valuable devices for measuring soil water balance components. Older lysimeter facilities are usually equipped with lever-arm-counterbalance weighing systems. A disadvantage of such systems is their sensitivity to external disturbances, mainly forces exerted by wind, which can significantly decrease measuring accuracy. Two types of smoothing functions were tested on a set of noisy lysimeter weighing data with respect to improved data interpretation. A basic piecewise sigmoid function was easy to adapt and gave proper results of typical diurnal variation of evapotranspiration on single days without rainfall. However, on a longer time period with rainfall events, a polynomial spline function performed better. Key words: Data management, resolution, accuracy, sigmoid, spline, smoothing.